In a wavelength division multiplexed (WDM) transmission system, it is possible for the power of an optical channel to be driven higher than a correct operating power level during amplification. For example, if a fiber cable is accidentally disconnected and then reconnected, a positive transient may occur during the reconnection due to the rapid increase in optical power at the input to the optical amplifier.
Generally speaking, a “primary” transient is caused by a loss of optical power in a first multiplexed group of optical channels, while “secondary” transients are caused by amplification mismatches between the surviving optical channels and subsequent portions of the network to which the surviving optical channels propagate. This mismatch may be due to errors in the transient suppression for amplifiers within the primary transient region.